Quinoa (Chenopodium quinoa Willd.), a nutritious and stress tolerant crop of the Amaranthaceae family, is rapidly gaining popularity as a functional food and nutraceutical (1). Quinoa's long history of use as a subsistence crop and wellness-promoting agent began 5,000-7,000 years ago as the “mother grain” of the ancient Incas. It was consumed for endurance properties by the Incan army, served to children and elders to promote growth and wellness, used to treat fractures and wounds, and incorporated in many medicinal formulations (2,3). Today the crop remains an important endurance-enhancing food source for rural indigenous people in South America and has found its way to kitchens throughout the world (1,4). Though quinoa is primarily grown in the Bolivian Altiplano, the crop is widely cultivated in South America (Columbia, Ecuador, Peru, Chile, and Argentina), as well as Europe, Asia, Africa, and North America.
Among agricultural food crops that have been regularly sold and consumed in the United States, quinoa is known to be a rich source of phytoecdysteroids (6,7). Phytoecdysteroids are polyhydroxylated steroids structurally related to insect molting hormones. The most prevalent phytoecdysteroid, 20-hydroxyecdysone (20-HE), has been extensively investigated for its insect defense properties (8). 20-HE, also known as ecdysterone or beta-ecdysone, has been shown to deter insect herbivory, delay development, and cause lethality to insect larvae (9-13).
Phytoecdysteroids have a wide range of therapeutic effects in mammals (8), including anabolic, performance enhancing (14, 15), anti-osteoporotic (16, 17) and wound healing properties (18). These molecules are considered the primary bioactive components of the traditional Chinese and Siberian herbs Ajuga turkestanica, Rhaponticum carthamoides, and Cyanotis vaga (15, 19, 20). Phytoecdysteroids, extracted from these botanical sources, have been marketed and sold in commercially available health products as adaptogens, body building agents, stress reducers, performance enhancers, and cosmetics (21).
Recent studies have demonstrated the role of 20-HE administration in metabolic syndrome (22, 23). Metabolic syndrome is a cluster of coexisting disorders including hyperglycemia/insulin resistance, excess abdominal fat, hypertension and dyslipidemia. Improvement in these metabolic conditions can greatly reduce an individual's likelihood of developing type 2 diabetes, cardiovascular disease, and stroke (24). Chronic administration of 20-HE (10 mg/kg body weight for 13 wk) to diet-induced obese, hyperglycemic mice significantly lowered blood glucose levels, increased insulin sensitivity, decreased body weight, and reduced adiposity 41% compared with control without affecting food consumption (22). Furthermore, a quinoa seed extract enriched to 1.9% 20-HE induced anti-diabetic and anti-obesity effects similar to administration of 20-HE alone (6 mg/kg body weight for 3 wk) in diet-induced obese, hyperglycemic mice (23).